Fix tasks leaked despite workspace window close (#35246)

Closes https://github.com/zed-industries/zed/issues/34932

Release Notes:

- Fixed tasks leaked despite workspace window close

crates/workspace/src/tasks.rs

@@ -73,7 +73,7 @@ impl Workspace {
 
         if let Some(terminal_provider) = self.terminal_provider.as_ref() {
             let task_status = terminal_provider.spawn(spawn_in_terminal, window, cx);
-            cx.background_spawn(async move {
+            let task = cx.background_spawn(async move {
                 match task_status.await {
                     Some(Ok(status)) => {
                         if status.success() {
@@ -82,11 +82,11 @@ impl Workspace {
                             log::debug!("Task spawn failed, code: {:?}", status.code());
                         }
                     }
-                    Some(Err(e)) => log::error!("Task spawn failed: {e}"),
+                    Some(Err(e)) => log::error!("Task spawn failed: {e:#}"),
                     None => log::debug!("Task spawn got cancelled"),
                 }
-            })
-            .detach();
+            });
+            self.scheduled_tasks.push(task);
         }
     }
 

crates/workspace/src/workspace.rs

@@ -1104,6 +1104,7 @@ pub struct Workspace {
     serialized_ssh_project: Option<SerializedSshProject>,
     _items_serializer: Task<Result<()>>,
     session_id: Option<String>,
+    scheduled_tasks: Vec<Task<()>>,
 }
 
 impl EventEmitter<Event> for Workspace {}
@@ -1435,6 +1436,7 @@ impl Workspace {
             _items_serializer,
             session_id: Some(session_id),
             serialized_ssh_project: None,
+            scheduled_tasks: Vec::new(),
         }
     }